IT201800020134A1 - METHOD AND SYSTEM TO READ / WRITE DATA FROM / TO RFID TAGS INTEGRATED / APPLIED TO / ON TIRES TRANSPORTED ON CONVEYOR BELTS - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

"METHOD AND SYSTEM FOR READING / WRITING DATA FROM / TO RFID TAGS INTEGRATED / APPLIED TO / ON TIRES TRANSPORTED ON CONVEYOR BELTS"

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method and a system for reading and / or writing data from / to radiofrequency identification tags (RFID - Radiofrequency Identification) integrated / incorporated in, or applied on / to tires transported on conveyor belts.

STATE OF THE TECHNIQUE

In the tire sector, there is a need for solutions that allow the univocal and automated identification of tires during their manufacture, use and disposal.

For example, with specific reference to the manufacture of tires, the unique and automated identification of tires can allow to optimize production processes and logistics operations, increase the use of automated control systems, perform an effective tire tracking / detection and, therefore, build smart tire factories.

In this context, the use of barcodes applied to tires to manage the production of tires and the production history of each tire is known. However, this solution has its limitations as printed barcodes run the risk of being erased or damaged during tire manufacturing and / or normal operation, thereby becoming unreadable or otherwise difficult to read.

In order to resolve these limitations, US 2016/0092814 A1 proposes to use a tire identification system based on radio frequency identification (RFID) tags. In particular, US 2016/0092814 A1 discloses a tire production management system using RFID tags, the operation of which includes: fixing an RFID tag on a tire before producing a finished tire in tire manufacturing processes; recognize the tire tag attached to the tire in each manufacturing process; and therefore manage the information according to a manufacturing process on a single tire. The Tire Production Management System according to US 2016/0092814 A1 includes: an RFID tag fixing part; a plurality of RFID readers; a plurality of management terminals for respective processes; a plurality of management servers; and a tire production management server. US 2016/0092814 A1 further discloses the code recognition of an RFID tag attached to a tire transported on a conveyor belt, in which the code recognition is performed by an RFID reader adjacent to said conveyor belt.

Furthermore, the Italian patent application n.

102016000009727 discloses a configurable and adjustable wireless radiofrequency sensor device which can be advantageously integrated / incorporated within, or applied to, a tire to provide automatic identification of the tire during its manufacture, during logistics operations and also during its normal operation. Furthermore, the configurable and adjustable radio frequency wireless sensor device according to 102016000009727 can be conveniently configured to further provide diagnostic data, such as for example temperature or pressure data.

PURPOSE AND SUMMARY OF THE INVENTION

The Applicant has carried out an in-depth study in order to develop an improved system and methodology to read and / or write data from / to RFID tags integrated / incorporated in, or applied to / on, tires transported on conveyor belts, thus conceiving the present invention.

Therefore, an object of the present invention is to provide a methodology and a system of the above type capable of providing, in general, excellent RFID-based read / write performance and, in particular, the unique detection of RFID tags with improved performance. compared to those of the currently known solutions.

This object is achieved by the present invention as the latter relates to a method and a system for reading and / or writing data from / to radio frequency identification (RFID) tags of tires transported on a conveyor belt, as defined in the claims attached.

More specifically, the present invention relates to a method for reading and / or writing data from / to RFID tags of tires transported on a conveyor belt in a transport direction, in which each tire is equipped with a respective RFID tag which stores an identification unique of said tire. This method includes providing:

• an antenna installed on or near the conveyor belt and configured for

- radiate radio frequency (RF) signals towards a coverage area on the conveyor belt, and - receive backscattered RF signals from said coverage area; And

• a reader connected to the antenna to operate the latter in transmission and reception.

The method also includes performing a preliminary calibration step which includes calibrating the reader:

a1) placing a given tire equipped with a given RFID tag on the conveyor belt and keeping said pneumatic datum immobile under / near the antenna;

a2) while the pneumatic data is kept motionless under / near the antenna,

- determining a minimum transmission power necessary to activate the given RFID tag,

- determining a calibration transmission power greater than said minimum transmission power, e

- irradiating, through the antenna, RF calibration signals with said calibration transmission power and receiving, through said antenna, RF calibration signals backscattered by the given RFID tag;

a3) while continuing to radiate the RF calibration signals and receive the backscattered RF calibration signals, incrementally moving the pneumatic datum back and forth on the conveyor belt until the given RFID tag stops responding;

a4) estimating a size of the coverage area parallel to the direction of transport on the basis of operation a3);

a5) by measuring

- first received power levels of the RF calibration signals received from the RFID tag data while the pneumatic data is kept motionless under / near the antenna and while said pneumatic data is moved back and forth, and

- second power levels received from the backscattered RF calibration signals received by the reader via the antenna while the pneumatic data is kept motionless under / near the antenna and while said pneumatic data is moved back and forth; a6) repeating the operations from a1) to a5) with different tires, thus obtaining

- a plurality of calibration transmission powers relating to the different tires, - a plurality of estimated dimensions of the coverage area relating to the different tires, and - a plurality of first and second power levels received relating to the different tires; and a7) by calculating

- an average transmission power based on the calibration transmission powers obtained, - an average size of the coverage area based on the estimated dimensions obtained,

- a query rate based on the average size of the coverage area and a given transport speed of the conveyor belt, - average levels of received power based on the first and second received power levels obtained, and

- one or more thresholds based on the average levels of power received.

In addition, the method also includes performing a read and / or write step which includes operating the calibrated reader to:

b1) radiate, through the antenna, one or more RF interrogation signals with the average transmission power and with the interrogation rate calculated in the preliminary calibration phase;

b2) receiving, via the antenna, one or more backscattered RF interrogation signals from a tire RFID tag passing through the coverage area, where said backscattered RF interrogation signal (s) carries (s) the unique identifier of the through tire;

b3) measure

- one or more third power levels received of the RF interrogation signal (s) received from the RFID tag of the passing tire, and

- one or more fourth power levels received of the backscattered RF interrogation signal (s) received by the reader via the antenna;

b4) detect the through tire by comparing the third (s) and fourth (s) of power levels received with the threshold (s) calculated in the preliminary calibration phase; And

b5) identify the passing tire detected on the basis of the unique identifier carried by the RF backscattered interrogation signal (s).

Conveniently, the reading and / or writing phase includes operating the calibrated reader also for:

b6) reading and / or writing data relating to the tire from / on the RFID tag of the passing tire.

Preferably, the antenna is configured to have a radiation pattern such as to determine that the coverage area covers:

• an entire width of the conveyor belt perpendicular to the direction of transport; And

• a limited length parallel to the direction of transport.

Conveniently, the antenna is planar and parallel to the conveyor belt, and has a predefined length parallel to the transport direction and a predefined width perpendicular to said transport direction, in which the predefined length is greater than the predefined width.

Preferably, the first, second, third and fourth levels of received power are indicative of phase and amplitude measurements of received power.

Furthermore, the present invention also relates to a system for reading and / or writing data from / to RFID tags of tires transported on a conveyor belt in a transport direction, in which each tire is equipped with a respective RFID tag which stores a unique identifier. of said tire. This system includes:

• an antenna installed on or near the conveyor belt and configured for

- radiate RF signals towards a coverage area on the conveyor belt, e

- receiving backscattered RF signals from said coverage area; And

• a reader that is connected to the antenna to make the latter work in transmission and reception, and is designed to be subjected to the preliminary calibration phase and, once calibrated, can be operated to perform the reading and / or writing phase of the above method according to the present invention.

Preferably, the system comprises a plurality of antennas which are:

• installed in different positions along the conveyor belt;

• each configured to radiate RF signals towards, and receive backscattered RF signals from, a respective coverage area on the conveyor belt; And

• connected to the reader to be operated in transmission and reception;

in which a position of each tire detected is determined, by the reader or by an electronic control unit connected to it or integrated / incorporated into it, on the basis of the antenna (conveniently, on the basis of the position of the antenna) it has received the backscattered RF interrogation signal (s) on the basis of which said tire was detected.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, some preferred embodiments, which are intended purely as non-limiting examples, will now be described with reference to the accompanying drawings (all not to scale), in which:

Figure 1 schematically illustrates an RFID gate according to a preferred (although not limiting) embodiment of the present invention;

• Figures 2, 3 and 4 show an example of a radiation diagram of an antenna of the RFID gate of figure 1;

Figure 5 schematically illustrates an example of a scenario for performing a preliminary calibration of the RFID gate of Figure 1; And

Figure 6 schematically illustrates an example of detecting a sequence of three tires passing through the RFID gate of Figure 1.

DETAILED DESCRIPTION OF PREFERRED FORMS OF REALIZATION OF THE INVENTION

The following description is presented to allow a person skilled in the art to make and use the invention. Various modifications to the embodiments shown and described will be easily apparent to those skilled in the art, without departing from the scope of the present invention as claimed. Therefore, it is not intended to limit the present invention to the embodiments shown and described, but the widest possible scope of protection must be granted in accordance with the principles and characteristics described herein and defined in the attached claims.

The present invention relates to the use of one or more RFID reading and / or writing systems (hereinafter referred to as RFID gates) installed along the path of a conveyor belt to monitor the tires transported on said conveyor belt and each equipped with of a respective RFID tag that stores data relating to the tire that includes a unique identifier of the tire and, conveniently, also additional information (for example, information indicating the model of the tire, the date and / or place of production, the materials of the tire, etc.).

The present invention can be advantageously exploited for automatic control, monitoring and tracking applications in (intelligent) systems for the production, sorting and disposal of tires using conveyor belts. In fact, using the present invention, it is possible to deploy RFID gates along the paths of the conveyor belts to control / monitor / track tires moving on said conveyor belts, in which the RFID gates, in use, read the data relating to the tire stored on the RFID tags of the passing tires and, if required, they can also conveniently write (ie, store) data on the same (for example, unique identifiers and / or, as previously explained, also additional information).

In particular, in use, an RFID gate according to the present invention has the ability to identify each passing tire in a single and univocal way, avoiding the problem of multiple readings from adjacent tires / conveyor belts. This allows you to automatically perform specific actions on each individual through tire and uniquely track / monitor the sequence of through tires.

For a better understanding of the present invention, Figure 1 schematically illustrates an RFID gate (indicated as a whole with 1) according to a preferred (although not limiting) embodiment of the present invention.

In particular, the RFID gate 1 includes an antenna 2 (conveniently, an array antenna) arranged above a conveyor belt 3 carrying tires 4 along (i.e., parallel to) a given direction of transport, in which each tire 4 is equipped with a respective RFID tag (not shown in Figure 1) which stores (at least) a unique identifier of said tire 4.

The antenna 2 is substantially planar and parallel both to the conveyor belt 3 and to a reference plane xy defined by:

• a first reference direction x parallel to the given direction of transport of the tires 4 on the conveyor belt 3; And

• a second reference direction y perpendicular to the first reference direction x (and, therefore, also orthogonal to said given transport direction).

Antenna 2 has a predefined length L along the (i.e., parallel to) the first reference direction x and a predefined width W along the (i.e., parallel to) the second reference direction y, where the predefined length L is greater than the predefined width W (i.e., L> W).

The antenna 2 is spaced from the conveyor belt 3, along (ie, parallel to) a third reference direction z orthogonal to the first and second reference directions x and y, by a predefined distance D.

Preferably, in order to facilitate the detection of passing tires 4, antenna 2 is a directional antenna configured to radiate and receive radio frequency (RF) signals to / from a coverage area that covers:

• an entire width of the conveyor belt 3 along the (ie, parallel to) the second reference direction y; And

• a limited length along (ie, parallel to) the first reference direction x.

Conveniently, the antenna 2 is a directional antenna configured to have a blade-shaped radiation pattern, which is oriented orthogonally to the given transport direction of the tires 4 on the conveyor belt 3 (i.e., perpendicular to the first reference direction x and parallel to the second reference direction y) and which has a main lobe covering the entire width of the conveyor belt 3 along the second reference direction y and a limited length along the first reference direction x.

In this regard, Figures 2, 3 and 4 show an example of a radiation pattern for antenna 2, respectively, in the reference space xyz, in the reference plane xz and in the reference plane xy (in Figures 3 and 4, the reference number 5 indicates an RFID tag applied to the tire 4 shown).

Conveniently, the antenna 2 can be operated to radiate / receive RF signals having frequencies in an Ultra High Frequency (UHF) band, preferably in a frequency range of 860 to 960 MHz, more preferably in a sub-range. frequencies from 865 to 868 MHz and / or a sub-range of frequencies from 902 to 928 MHz.

In addition, optional requirements for antenna 2 can conveniently include:

• gain greater than 0 dB;

• operation based on circular polarization; • beam width of less than 90 ° at least on a single plane.

Again with reference to Figure 1, the RFID gate 1 also includes a reading and / or writing unit / device 6 (hereinafter simply referred to as a reader, for the sake of brevity) connected / or to the antenna 2 in a wired manner, for example by means of a coaxial cable. Furthermore, a control and processing unit 7 (for example, a computer) is connected locally or remotely to the reader 6 to control its operation. In this regard, it is worth noting that the control and processing unit 7 could also be conveniently integrated / incorporated into the reader 6.

Conveniently, the reader 6 can be connected to a plurality of antennas 2 installed in different positions along the path of the conveyor belt 3. For example, the reader 6 can be conveniently connected to up to four antennas 2 directly or through a multiplexer (for example , time / power division strategies could be conveniently adopted to power the different antennas 2).

Additionally, additional requirements for reader 6 may conveniently include:

• support for the entire frequency range from 860 to 960 MHz, or for the aforementioned sub-ranges of frequencies;

• ability to support multiple antenna connections and be operated down to a level of +31.5 dBm;

• ability to be operated with separate read and write levels and adjustable power on command, eg from 5 dBm to 31.5 dBm with at least an accuracy of +/- 0.5 dBm.

In the light of what has been explained above, in use, when the tires 4 are transported on the conveyor belt 3, the RFID gate 1 is able to uniquely detect and automatically identify each tire 4 passing under the antenna 2. Therefore, a system of control / monitoring that uses a plurality of RFID gates 1 (and / or a plurality of antennas 2 connected to one or more readers 6) installed along the path of the conveyor belt 3 (or along the paths of a plurality of conveyor belts 3) is able to accurately locate each tire 4 in motion.

Furthermore, by conveniently using an adequate processing of the transmitted and received RF signals (in amplitude, phase and time), it is also possible to monitor / track the sequence of the tires 4 passing from / from each RFID gate 1 (or, in the case of multiple antennas 2 connected to one or more readers 6, the sequence of tires 4 passing under each antenna 2).

Furthermore, the / each reader 6 can be conveniently configured for:

• read, in addition to the unique identifiers of the tires, also additional data relating to the tire stored on the RFID tags 5 of the 4 through tires (for example, information indicating the model of the tire, the date and / or place of production, the materials of the tire, etc.); And,

• if required, also write (ie, store) data on the RFID tags 5 of the 4 through tires.

In this regard, it is worth noting that, as it is clear, the / each reader 6 can be conveniently used to write also the unique identifiers on the RFID tags 5.

Read and / or write operations can be conveniently controlled by:

• the control and processing unit 7 connected to all the readers 6 used, in which said control and processing unit 7 is configured (in particular, it is programmed) to selectively control each reader 6 to execute one or more respective predefined read and / or write operations; or

• a central control unit connected remotely to all the control and processing units 7 used, in which said central control unit is configured (in particular, it is programmed) to selectively control each control and processing unit 7 so as to cause the latter to selectively control each reader 6 connected to it to perform one or more respective predefined read and / or write operations.

More generally, a method for reading and / or writing data from / to RFID tags 5 of tires 4 transported on a conveyor belt 3 according to a preferred embodiment of the present invention includes:

• a preliminary calibration phase which includes calibrating the reader 6, in which said preliminary calibration phase is conveniently performed once the RFID gate 1 has been installed or if the surrounding environment is subject to substantial alterations that can affect the scenario of RF communication (for example, variations in the positions of scattering objects); And

• a reading and / or writing phase performed by operating the calibrated reader 6.

Hereinafter, a preferred (although not limiting) embodiment of said method will now be described in detail with specific reference to the RFID gate 1, i.e. in the case of a single antenna 2, a single reader 6 and a single control and processing unit 7 , remaining clear that the following teachings can be applied, mutatis mutandis, to different system architectures which involve the use of one or more control and processing units 7, each connected to one or more readers 6, each connected to one or more antennas 2 (which can also conveniently have a different spatial arrangement with respect to the conveyor belt, for example, they can be arranged adjacent / close to one of its edges).

Preferably, the detection of RFID tags is based on a combined use of phase and power amplitude of the RF signals transmitted by the reader 6 through the antenna 2 to an RFID tag 5 and backscattered from the latter to the antenna 2 and, therefore, received by the player 6.

Conveniently, some preliminary operations can be common both to the preliminary calibration phase and to the reading and / or writing phase, such as:

• connect the reader 6 to the control and processing unit 7 by selecting an appropriate communication port / interface (for example, Ethernet, serial, USB, wifi, etc.);

• selecting a reader 6 (if multiple readers 6 are used) and one of its antenna 2 (or one of its antenna 2, if a plurality of antennas 2 is connected to / to each reader 6);

• define specific interrogation methods in terms of operating frequency, interrogation rate (that is, the number of interrogations per second (or in other time units)) and emitted power.

Conveniently, at the beginning of a communication from reader to tag, reader 6 activates an RFID tag 5 passing under antenna 2 by sending a continuous wave. Subsequently, the activated RFID tag 5 receives commands from the reader 6 and, finally, sends back the data (that is, the unique identifier and / or the additional data relating to the tire) through a backscattered modulation of the continuous wave received by the RFID gate 1. The transmitted and backscattered powers are measured in terms of received signal strength indicators (RSSI - Received Signal Strength Indicator) on the reader side (RSSIR, in amplitude and phase) and on the RFID tag side (RSSIT, in amplitude and phase) .

For a better understanding of the preliminary calibration step, a preferred (although not limiting) embodiment thereof will be described in detail below.

In this regard, figure 5 schematically illustrates an example of a scenario to perform the preliminary calibration of reader 6.

In particular, as shown in Figure 5, a tire 41 equipped with an RFID tag 51 is conveniently positioned on the conveyor belt 3 just below the antenna 2, and a minimum power (Pmin) to be emitted by the reader 6 through the antenna 2 for activating the RFID tag 51 is conveniently determined (preferably, by implementing an ignition power measurement procedure).

Subsequently, the PTX transmit power value = Pmin Psm - where Psm indicates a safety margin (for example, equal to 3 dB) - is conveniently set to ensure a rather robust communication between the reader 6 and the RFID tag 51 a regardless of the position of the RFID tag 51 in / on the tire 41 (polar orientation).

Said PTX transmission power is, therefore, used to transmit RF signals from antenna 2, while the RSSI values are measured both from the RFID tag side and from the reader side (RSSIT, RSSIR), both in amplitude / module and in phase. .

Next, a size of a coverage area 21 of the antenna 2 on the conveyor belt 3 (i.e., the area in which there is the greatest possibility of the RFID tag 51 being detected) can be determined experimentally by moving incrementally a tire 41 back and forth (manually or by operating the conveyor belt 3) from its initial position until the RFID tag 51 stops responding. In this regard, it should be noted that the size of the coverage area typically depends on the specific configuration used (ie, the PTX transmission power, the antenna beam width, the type of conveyor belt, etc.).

In order to reduce the multiple responses from RFID tags 51, 52, 53 of adjacent tires 41, 42, 43, it is advisable to adequately space the adjacent tires 41, 42, 43 on the conveyor belt 3 so as to have only one tire 41/42 / 43 at a time within the determined coverage area 21 (for example, assuming an approximate reading volume of ellipsoidal shape 22, it can conveniently be assumed that the minimum distance dmin between adjacent tires 41, 42, 43 is greater of a semi-major axis x / 2 of the coverage area 21 parallel to the transport direction of the tires 41, 42, 43 on the conveyor belt 3).

For more information about RFID coverage, refer, for example, to G. Casati et al., "The Interrogation Footprint of RFID-UAV: Electromagnetic Modeling and Experimentations", IEEE Journal of Radio Frequency Identification, Volume 1, Edition 2 pages 155-162, 25 October 2017.

Conveniently, in order to take into account the variability of the installation configuration, the above procedure is repeated N times (for example, at least three times) with different tires 41, 42, 43 to determine an average value of PTX-av transmission power, average RSSI values RSSIT-av, RSSIR-av (amplitude and phase) and an average size of the coverage area 21.

Therefore, at the end of the preliminary calibration phase, the transmission power value to be used to carry out the reading and / or writing phase is set equal to PTX-av, while the average RSSI values RSSIT-av, RSSIR-av are used to set one or more thresholds to be used to detect passing tires and to distinguish between multiple readings (for example, due to tires not spaced enough, multiple tires on adjacent conveyor belts, stochastic multi-path phenomena, etc.).

Different threshold calculation choices can be conveniently adopted on the basis of the average RSSI values RSSIT-av, RSSIR-av depending on various factors, such as for example the specific configuration used (i.e., the PTX transmission power, the beamwidth d antenna, type of conveyor belt, etc.). For example, it is possible to calculate:

• a single overall threshold for use with all RSSI measures; or

• an amplitude threshold for all RSSI amplitude measurements and / or a phase threshold for all RSSI phase measurements; or also,

• four thresholds, i.e. a first amplitude threshold and a first phase threshold for, respectively, the RSSI amplitude and phase measurements performed on the side of the RFID tag, and a second amplitude threshold and a second phase threshold for, respectively, the RSSI phase and amplitude measurements from the reader side.

The final choice on the calculation of the threshold for a particular configuration / installation can be conveniently made on the basis of evaluations carried out during the preliminary calibration phase carried out for this particular configuration / installation.

Furthermore, in the preliminary calibration phase it is also possible to determine an interrogation rate to be used to detect passing tires. In fact, being x the determined average size of the coverage area along the transport direction of the tires on the conveyor belt (for example, the major axis of the elliptical coverage area 21 shown in Figure 5) and vX the speed of the transported tires (which can be considered reasonably constant), it is possible to determine a time tX required for a tire to cover the entire coverage area or, equivalently, the time a tire is within the coverage area. Therefore, an interrogation rate used by reader 6 to detect passing tires can be conveniently determined so as to have at least one interrogation within time tX.

Furthermore, for a better understanding of the reading and / or writing step, a preferred (although not limiting) embodiment of tire detection operations performed in said reading and / or writing step will be described in detail below.

Conveniently, during normal operation, reader 6 continuously transmits "reading" commands via antenna 2 using, as the transmission power value, the average value of PTX transmission power-

av determined in the preliminary calibration phase, in which PTX-av is such as to allow reading only one RFID tag passing under the antenna.

Furthermore, the thresholds calculated in the preliminary calibration phase on the basis of the average RSSI values RSSIT-av, RSSIR-

av are used to detect RFID tags passing under antenna 2 and to distinguish between multiple readings (which, as previously explained, could be caused by insufficient distance between adjacent tires on one or the same conveyor belt, or by the presence of multiple tires on adjacent conveyor belts, or a stochastic phenomenon of multi-path, etc.).

Conveniently, the detection of an RFID tag can be summarized in the following way:

• if RSSIR / T-m ≥ RSSIth, then an RFID tag (and therefore a tire) is detected or,

• if RSSIR / T-m <RSSIth, then an RFID / tire tag is not detected (for example, it could be before / after antenna 2 on the same conveyor belt 3 or on an adjacent conveyor belt),

where RSSIR / T-m indicates the RSSI value (s) of amplitude and / or phase measured at the reader and / or the RFID tag, and RSSIth indicates the threshold (s) determined, as previously explained , in the preliminary calibration phase on the basis of the average RSSI values RSSIT-av, RSSIR-

av.

Conveniently, the RSSIth threshold (s) can also be modified dynamically and in real time in order to adapt the detection to a particular installation and / or environment (for example, by adding an offset value to improve robustness / detection reliability).

Conveniently, adequate processing of the temporal variation of the RSSIR / T-m value (s) also allows you to monitor / track the sequence of through tires, as shown in Figure 6, which schematically illustrates:

• above, a sequence of three through tires A, B, C, each equipped with a respective RFID 5A / 5B / 5C tag; and, • below, corresponding RSSI values measured over time (assuming that tires A, B, C are moving with a speed of 1 m / s and are spaced 100 cm apart, and that a reading power of 30 dBm is used ).

According to the foregoing, the technical advantages and innovative features of the present invention are immediately clear to those skilled in the art.

In particular, it is important to underline that the present invention provides, in general, excellent RFID-based read / write performance and, in particular, a unique detection of RFID tags with improved performance compared to currently known solutions.

Therefore, the present invention is advantageously usable for automatic control, monitoring and tracking applications in (intelligent) tire manufacturing, sorting and disposal plants using conveyor belts.

Furthermore, the present invention makes it possible to create databases of tire inventories which store significant data relating to each tire produced and which are accessible (for example, via the Internet) to interested parties (for example, manufacturing operators, logistics operators, retailers, customers, etc.).

Finally, it is clear that numerous modifications and variations can be made to the present invention, all falling within the scope of protection of the invention, as defined in the attached claims. In this regard, it should be noted that, although the invention has been previously described with specific reference to an antenna arranged on a conveyor belt, the teachings of the present invention can be immediately applied, mutatis mutandis, to different spatial configurations / arrangements of the antenna with respect to the conveyor. For example, the antenna can be conveniently installed along a lateral edge of the conveyor belt, adjacent to, in proximity to, said conveyor belt, extending perpendicularly to, or inclined with respect to, the plane of the conveyor belt (i.e., the aforementioned reference plane xy) and parallel to the transport direction. More generally, the antenna could be arranged close to the conveyor belt, however having a radiation pattern such as to determine a coverage area that covers an entire width of the conveyor belt perpendicular to the direction of transport and a limited length parallel to said transport direction (conveniently, the antenna being planar and having a predefined length parallel to the transport direction and a predefined width perpendicular to said transport direction, the predefined length being greater than said predefined width).

Claims (9)

CLAIMS 1. Method for reading and / or writing data from / to radio frequency identification tags (5, 5A, 5B, 5C) of tires (4, A, B, C) transported on a conveyor belt (3) in a direction of transport, in which each tire (4, A, B, C) is equipped with a respective radiofrequency identification tag (5, 5A, 5B, 5C) which stores a unique identifier of said tire (4, A, B, C ); the method comprising providing: • an antenna (2) installed on or near the conveyor belt (3) and configured for - radiate radio frequency signals towards a coverage area (21) on the conveyor belt (3), and - receive backscattered radio frequency signals from said coverage area (21); And • a reader (6) connected to the antenna (2) to operate the latter in transmission and reception; the method further comprising performing a preliminary calibration step which includes calibrating the reader (6): a1) placing a pneumatic datum (41) equipped with a radiofrequency identification tag (51) on the conveyor belt (3) and keeping said pneumatic datum (41) immobile under / near the antenna (2); a2) while the pneumatic data (41) is kept motionless under / near the antenna (2), - determining a minimum transmission power necessary to activate the given radiofrequency identification tag (51), - determining a calibration transmission power greater than said minimum transmission power, e - irradiating, through the antenna (2), calibration radiofrequency signals with said calibration transmission power and receiving, through said antenna (2), calibration radiofrequency signals backscattered by the given radiofrequency identification tag (51); a3) while continuing to radiate calibration radiofrequency signals and receive backscattered calibration radiofrequency signals, incrementally moving the pneumatic datum (41) back and forth on the conveyor belt (3) until the given radiofrequency identification tag (51) does not stop responding; a4) estimating a size (aX) of the coverage area (21) parallel to the direction of transport on the basis of operation a3); a5) by measuring - first received power levels of the calibration radiofrequency signals received by the given radiofrequency identification tag (51) while the pneumatic datum (41) is kept motionless under / near the antenna (2) and while said pneumatic datum (41) is shifted back and forth, and - second received power levels of the backscattered calibration radiofrequency signals received by the reader (6) via the antenna (2) while the pneumatic datum (41) is kept motionless under / near the antenna ( 2) and while said pneumatic datum (41) is moved back and forth; a6) repeating the operations from a1) to a5) with different tires (41, 42, 43), thus obtaining - a plurality of calibration transmission powers relating to the different tires (41, 42, 43), - a plurality of estimated dimensions (x) of the coverage area (21) relating to the different tires (41, 42, 43), and - a plurality of first and second received power levels relating to the different tires (41, 42, 43); And a7) by calculating - an average transmission power based on the obtained calibration transmission powers, - an average size of the coverage area (21) based on all the estimated dimensions (x) obtained, - a query rate based on the average size of the coverage area (21) and a given speed of transport of the conveyor belt (3), - average received power levels based on the first and second received power levels obtained, e - one or more thresholds based on the average levels of received power; wherein the method further comprises performing a reading and / or writing step which includes operating the calibrated reader (6) to: b1) radiate, through the antenna (2), one or more radio frequency interrogation signals with the average transmission power and the interrogation rate calculated in the preliminary calibration phase; b2) receive, through the antenna (2), one or more radio frequency interrogation signals backscattered by a radio frequency identification tag (5, 5A, 5B, 5C) of a passing tire (4, A, B, C) through the coverage area (21), in which said backscattered radio frequency interrogation signal (s) carry / carry the unique identifier of the passing tire (4, A, B, C); b3) measure - one or more third power levels received of the radio frequency interrogation signal (s) received by the radio frequency identification tag (5, 5A, 5B, 5C) of the passing tire (4, A, B, C), and - one or more fourth power levels received of the backscattered radio frequency interrogation signal (s) received by the reader (6) via the antenna (2); b4) detect the through tire (4, A, B, C) by comparing the third (s) and fourth (s) received power levels with the threshold (s) calculated in the preliminary calibration phase; And b5) identify the detected passing tire (4, A, B, C) on the basis of the unique identifier carried by the backscattered radio frequency interrogation signal (s). The method of claim 1, wherein the reading and / or writing step includes operating the calibrated reader (6) also for: b6) reading and / or writing data relating to the tire from / on the radiofrequency identification tag (5, 5A, 5B, 5C) of the through tire (4, A, B, C). 3. The method according to claim 1 or 2, in which the antenna (2) is configured to have a radiation pattern such as to determine that the coverage area (21) covers: • an entire width of the conveyor belt (3) perpendicular to the direction of transport; And • a limited length parallel to said transport direction. The method according to any one of claims 1-3, wherein the antenna (2) is planar and parallel to the conveyor belt (3), and has a predefined length (L) parallel to the transport direction and a predefined width ( W) perpendicular to said transport direction, where the predefined length (L) is greater than the predefined width (W). The method according to any preceding claim, wherein the first, second, third and fourth received power levels are indicative of phase and amplitude measurements of received power. 6. System (1) to read and / or write data from / to radio frequency identification tags (5, 5A, 5B, 5C) of tires (4, A, B, C) transported on a conveyor belt (3) in a transport direction, in which each tire (4, A, B, C) is equipped with a respective radiofrequency identification tag (5, 5A, 5B, 5C) which stores a unique identifier of said tire (4, A, B, C); the system (1) comprising: • an antenna (2) installed on or near the conveyor belt (3) and configured for - radiate radio frequency signals to a coverage area (21) on the conveyor belt (3), and - receive radio frequency signals from radio frequency identification tags (5, 51, 52, 53, 5A, 5B, 5C) of tires (4, 41, 42, 43, A, B, C) passing through said coverage area (21); and • a reader (6) connected to the antenna (2) to operate the latter in transmission and reception; wherein the reader (6) is designed to be subjected to the preliminary calibration step and, once calibrated, is operable to perform the reading and / or writing step of the method as claimed in any one of the preceding claims. 7. The system of claim 6, in which the antenna (2) is configured to have a radiation pattern such as to determine that the coverage area (21) covers: • an entire width of the conveyor belt (3) perpendicular to the direction of transport; And • a limited length parallel to said transport direction. The system according to claim 6 or 7, wherein the antenna (2) is planar and parallel to the conveyor belt (3), and has a predefined length (L) parallel to the transport direction and a predefined width (W) perpendicular to said transport direction, where the predefined length (L) is greater than the predefined width (W). The system according to any one of claims 6-8, comprising a plurality of antennas (2) which are: • installed in different positions along the conveyor belt (3); • each configured to radiate radiofrequency signals towards, and receive backscattered radiofrequency signals from, a respective coverage area (21) on the conveyor belt (3); and • connected to the reader (6) to be operated in transmission and reception; in which a position of each tire detected (4, A, B, C) is determined, by the reader (6) or by an electronic control unit (7) connected to it or integrated / incorporated into it, on the basis of the antenna (2) which received the backscattered radiofrequency interrogation signal (s) on the basis of which said tire (4, A, B, C) was detected.